brown



July 6, 1948.

T. w. BRQWN COMBINED TACHOMETER AND ACCELEROMETER 6 Sheets-Sheet 1 Filed Dec. 15, 1945 July 6, 1948. I T. w. BROWN 2,444,630

COMBINED TACHOMETER AND ACCELEROMETER Fi1 ed Dec. 15, 1945 6 Sheets-Sheet 2 Jilly 6, 1 948. w, BRQWN 2,444,630

COMBINED TACHOMETER AND EEEEEEEEEEE ER Filed Dec. 15, 1945 1 e Sheets-She et 3 July 6, 1948.

T. W. BROWN COMBINED TKCHOMETER AND ACCELEROMETER 6 Sheets-Sheet 4 Filed Dec. '15. 1945 dag,

y 6, 1948. T. w. BROWN 2, 44,630

COMBINED TACHOMETER AND ACCELEROMETER Filed Dec. 15, 1945 6 Sheets-Sheet 5 itve'illii 7 y 6, 1948. T. w. BROWN COMBINED TACHQMETER AND ACCELEROMETER G Sheets-Sheet 6 Filed Dec. 15, 1945 Patented July 6, 1948 COMBINED TACHOMETER-AND ACCELEROMETER/ Thomas W. Brown, Framingham', Mass, assigncrto Lombard Governor? Corporation; Ashland, Mass, a corporation of Massachusetts Application'Decembcr 15, 1945,-Serial No. 635,387

This invention relates to a combined tachometer and accelerometer for. measuring or controlling speed, or both.

. The object of the invention, broadly stated, is the provision of such an instrument. that will respond to changes inacceleration linearly, that. is, one unit of acceleration will produce oneunit of force regardless of the actual speed or the position of the speed responsive element.

By the addition. of. the usual equipment, including a valve actuated by my improved tachometer and accelerometer; a servomotor and source of fiuid' pressure, between which and said: servomotor said valve is interposed; an extremely sensitive and quick acting precision. governor for controlling the speed of a prime mover, such as a water turbine, is produced;

Another object of the invention is to provide an instrument of the class described wherein the effect of a retractile spring in opposing the change of position of a rotating member produced by centrifugal force is rendered substantially constant throughout the range. of speeds for which the apparatus is designed.

Other objects of my invention and the new and useful results effected thereby will appear from the detailed description of the particularembodiment thereof selected for'illustration.

In the accompanying drawings'illustrating an embodiment of my invention which has given good results in practice;

Figure l is a central vertical section takencn the line I! of Fig. 3.

Fig. 2 is a horizontal section taken on the line 2-2 of Fig. 1

Fig. 3 is a horizontal section taken'on the line 33 of Fig. 1.

Fig. 4 isa front elevation, partly in section.

Fig. 5 is avertical section taken on' the line 5'-5 of Fig. 3.

Fig.-6- is an elevationof a-compound roller as- Fig. 1-1 isanelevation of said'ring and helic'al cams.

Fig. 121s a perspectiveviewof one of said helicar cams and its co-operating follower.

Fig. l3 is a fragmentary view illustrating-a modified-form of cam th'atmay'be employed.

My invention in its present form comprises four horizontal rotatable discs which m'a'y bel characterized as follows:

A cam follower disc 2 a flywheel disc 2'2, a cam carrying disc 24; and a connection disc 26;' whereby the assembly is connected'toqsome' form ofspeed-indicating or speed control device.- The discs 20 and Zli'are rigidly'connected'by'holdf'ast' means spaced equidistantly around the disc and constitute a rotatable frame interposed between:

I the prime moveror machine thespeed-of which 4 tween the flywheel disc and the-cam' disc, and

the'walls thereof, in co-operation with saidposts; forming stops to limit such tangential motion. At all times, the discs 20, '24; 2t, rotate together at identical speeds but a change in the speed of the prime mover will cause tangential move-- ment between such disc assembly and the disc 22,

as hereinafter explained;

Rotary movement is imparted to the whole disc disc 24 together and secure the same. to the prime mover shaft. Three spaced pins 38 (Figs. 1 and 3) are employed to reinforce the connection be-' tween said hub and the disc '24. I

Surrounding the hub 24 is a flanged .sleeve' All from the flange 4| of which rise three pairs of brackets 45, 4T, equidistantly spaced around said flange. Disposed between each pair of brackets is roller 42 mounted for rotation on an axle 44.: (Figs. 1- and 9) by ball bearing mounts. r

Each roller co-operates with a flat 48 mille into the peripheral surface of the upper end por tion ofthe hub, the plane passing through eacln with which they co-operate. The resulting tangential motion of the helical cams with respect to their co-operating rollers 92 is accompanied by a definitely related vertical axial motion of the flywheel disc with respect to the sleeve 99, and such motion will raise the disc assembly 28, 26, thereby moving the rod 15 upwardly and actuating the indicating or control apparatus above referred to as connected for actuation by said rod. In like manner, negative acceleration will have the opposite effect, and the rod 19 will move downwardly.

The response of the rod 15 to acceleration will be linear, that is to say, one unit of acceleration will produce one unit of force for all speeds throughout the range for which the apparatus is designed, and regardless of the position of the roller assemblies 63, 6B, or the disc assembly 29, 25.

It has been found in practice that when the rod 15 is attached to the usual equipment used in connection with speed governors to control the supply of energy to prime movers, the present invention provides an extremely sensitive and quick acting precision governor, even although no dash pot or other antiracing appliances are used. The salient feature of the invention and one of the contributing causes of the precision and sensitiveness of the apparatus is the reduction of friction between the cams and their respective followers to a negligible amount by virtue of the rollin contacts between these elements and by the holding of such contacts to a minimum number.

Having thus described illustrative embodiments of my invention without, however, limiting the same thereto, what I claim and desire to secure by Letters Patent is:

A combined tachometer and accelerometer comprising in combination, a rotatable member, a central hub secured to said member, said hub being constructed and arranged for attaching said member for rotation to a rotating element, a sleeve disposed around said hub for rotary movement therewith and axial movement thereto, a follower carried by said sleeve for rotary movement therewith, a cam carried by said rotatable member, a roller assembly interposed between said follower and said cam, said roller assembly having rolling contact with said follower and said cam, a flywheel mounted for rotation around said sleeve, a cam mounted on said flywheel, and a follower mounted on said rotatable member for co-operation with th cam last mentioned.

THOMAS W. BRO-WN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 805,392 Warren Nov. 21, 1905 959,853 Grant 1 May 31, 1910 1,130,659 Baldwin Mar. 2, 1915 1,135,054 Schacht Apr. 13, 1915 1,352,189 Haeberlein Sept. '7, 1920 1,880,815 Cole Oct. 4, 1932 2,146,046 Bancroft Feb. 7, 1939 2,157,542 Kieser May 9, 1939 FOREIGN PATENTS Number Country Date 185,473 Germany July 1, 1907 420,429 Germany Oct. 23, 1925 "r. B. Cl-[ACE MIXER VALVE AND CONTROL July 6, 1948.

3 Sheets-Sheet 1 Filed March 10, 1944 

